The present invention relates generally to an IC chip package, and more particularly to a small size IC chip package.
FIG. 1 illustrates an IC chip package according to the prior art. The package 10 comprises generally a substrate 11, a chip 12, and a cover 13. The substrate 11 has a top-open receiving chamber 14 and a certain number of connecting pads 16 of predetermined shapes arranged in the receiving chamber 14 at the bottom. The chip 12 is adhered to the central portion of the bottom of the receiving chamber 14, and electrically connected to the connecting pads 16 by bonding wires 17. The cover 13 closes the open side of the substrate 11 to protect the chip 12 against external impact or pollutant. The cover 13 shall be made of transparent material in case the chip 12 is a video chip.
In the aforesaid package 10, the bottom of the receiving chamber 14 must receive the chip 12 and the connecting pads 16 of the substrate 11, and sufficient space should be provided between the chip 12 and the wall of the receiving chamber 14 for the movement of the wire bonding tool 18, and therefore, the area of the bottom of the receiving chamber 14 must be much greater than the chip. Due to the aforesaid reasons, this package does not meet the requirements for light, thin, small, and short electronic products.
Further, if the manufacturing of the substrate 11 of the aforesaid package 10 is based on plastic printing circuit board, moisture will pass to the inside of the receiving chamber 14 after a long use, thereby affecting the functioning of the chip 12. In order to eliminate this problem, a waterproof isolating layer must be added to the bottom of the receiving chamber 14. However, the installation of this isolating layer is complicated because the presence of the isolating layer must not interfere with the connection between the bonding wires 17 and the connecting pads 16. Improper installation of the isolating layer cannot achieve the desired waterproof effect. Some manufacturers use ceramic material to make the substrate 11 instead of plastic material. However, the manufacturing cost of a ceramic printing circuit board is much higher than a plastic printing circuit. Further, ceramic material cannot isolate moisture completely.
The primary object of the present invention is to provide an IC chip package, which achieves the requirement for small dimensions.
It is another object of the present invention to provide an IC chip package, which effectively isolates moisture and, is inexpensive to manufacture.
To achieve these objects of the present invention, the IC chip package of the present invention comprises a substrate, the substrate having a top side, a bottom side, and a receiving chamber, the receiving chamber having an opening disposed in the top side, the top side of the substrate having a plurality of connecting pads arranged around the opening of the receiving chamber; a chip fixedly mounted in the receiving chamber of the substrate, the chip comprising a plurality of connecting pads; a plurality of bonding wires respectively electrically connected between the connecting pads at the substrate and the connecting pads at the chip; adhesive means provided in the connecting area between the bonding wires and the connecting pads of the substrate; and a cover fixedly fastened to the adhesive means to close the opening of the receiving chamber.